Production of halogenated halocyclopentadiene adducts of styrene

ABSTRACT

A process is described for preparing halogenated halocyclopentadiene adducts of styrene by reacting a styrene derivative with a halogenated cyclopentadiene in a Diels-Alder reaction, and then halogenating the aromatic ring to contain between 1 and 5 halogen atoms. The resulting compounds are useful as fire retardant additives in various elastomers and plastics, especially acrylonitrilebutadiene-styrene (ABS).

United States Patent 1 1 Carlson et al.

1 1 Jan. 16,1973

[ 1 PRODUCTION OF HALOGENATED HALOCYCLOPENTADIENE ADDUCTS OF STYRENE[75] lriventors: Richard D. Carlson, Grand Island; James L. Dever,Lewiston, both of NY.

[73] Assignee: Hooker Chemical Corporation, Niagara Falls, NY.

[22] Filed: June 29, 1970 [21] Appl. No.: 51,009

[52] U.S. Cl. ..260/64 9 R, 252/8.1, 210/615.7 R,

260/649 F, 260/880, 260/D1G. 24 [51] Int. Cl ..C07c 25/18 [58] Field ofSearch....260/649 R, 649 F, 650, 611 A [56] References Cited UNITEDSTATES PATENTS i FORElGN PATENTS OR APPLlCATlONS 651,528 4/1951 GreatBritain ..260/649 R 652,112 4/1951 Great Britain.... 260/649 R 860,19812/1952 Germany 260/650 R 991,067 5/1965 Great Britain 260/649 R 986,6343/1965 Great Britain ..260/65O R 737,793 10/1955 Great Britain "260/641R OTHER PUBLICATIONS Roberts et al., J. Org. Chem., 28, 1439-4440, 1963.Williamson et al., J.A.C.S., 86, 40214025, 1964.

Primary ExaminerHoward T. Mars Attorney-Peter F. Casella, Donald C.Studley, Richard P. Mueller, James F. Mudd and William J. Schramm [57]ABSTRACT A process is described for preparing halogenatedhalocyclopentadiene adducts of styrene by reacting a styrene derivativewith a halogenated cyclopentadiene in a Diels-Alder reaction, and thenhalogenating the aromatic ring to contain between 1 and 5 halogen atoms.

The resulting compounds are useful as fire retardant additives invarious elastomers and plastics, especiallyacrylonitrile-butadiene-styrene (ABS).

15 Claims, No Drawings PRODUCTION OF HALOGENATED HALOCYCLOPENTADIENEADDUCTS OF STYRENE BACKGROUND OF THE INVENTION The need for fireretardant additives in plastics has been increasing substantially in thepast few years, particularly because of the Fabric Flammability Act anda number of other legislative measures. Halogenated derivatives havebeen a good source of fire retardant additives. Accordingly therefore,improved processes for producing said derivatives are required. A numberof patents have issued describing processes for preparing variousDiels-Alder adducts of halogenated cyclopentadienes. Among them are US.Pat. Nos.- 2,606,910; 2,952,711; 2,952,712; 3,043,795 and 3,397,175.None of the above patents describes a simple economic method forproducing the desired halogenated halocyclopentadiene styrene adducts.

It is an object of this application to produce in an economic mannerhalogenated cyclopentadiene adducts of styrenes. It is also an object toproduce in high yields halogenated halocyclopentadiene adducts ofstyrenes.

SUMMARY OF THE INVENTION Halogenated cyclopentadiene adducts of styreneare prepared by reacting a styrene derivative with a halogenatedcyclopentadiene. The resulting Diels- Alder adduct is halogenated toproduce between one and five halogen atoms on the aromatic ring.

The processing steps employ relatively inexpensive reactants and areconducted in a direct manner.

DESCRIPTION OF PREFERRED EMBODIMENTS Halogenated cyclopentadiene adductsof styrene are prepared comprising (1) reacting a styrene derivative ofthe following structure C=CH2 wherein R and R are independently selectedfrom the group consisting of hydrogen and lower alkyl of one to sixcarbon atoms, with a halogenated cyclopentadiene of the structure Y X Xhalogen on the aromatic ring, only up to four bromine atoms may besubstituted thereon.

The molar ratio of reactants employed in step 1 ranges from about 0.05moles to approximately 5 moles of halogenated cyclopentadiene per moleof styrene, preferably 0.5 to 2 moles of halogenated cyclopentadiene permole of styrene and even more preferably on an equal molar ratio. Thetemperature of the first step, i.e., Diels-Alder addition ranges fromabout 50C. to about 250 C., preferably about C. to about 180 C. and evenmore preferably from about C. to about 170 C. The temperature employedin the halogenation step ranges from about --50 C. to about C.,preferably from about 10 to about 1 10 C.

In the halogenation reaction, catalysts can be employed such as metalsor metal halides, preferably the metal chloride or bromide; examples ofsome metals that may be used as catalysts are aluminum, zinc, iron,bismuth, titanium, copper, tellurium, mercury, lead, magnesium, cadmium,selenium, antimony and molybdenum; the aforementioned metals may be usedas their chlorides or bromides in their role as catalysts. The amount ofhalogenation catalyst employed, on a weight percentage basis of theamount of adduct reactant, ranges from about 0.01 percent to about 10.0percent.

The first reaction may be carried out in the absence of solvents.However, solvents inert to reactants and products may be used, such as,perchloroethylene, trichloroethylene, cyclohexane, etc. Solvents thatmay be employed in the halogenation step are solvents inert to thereactants and the reaction products. Such solvents are halogenatedaliphatics such as acetylene tetrachloride, trichloromethane,hexachlorobutadiene, methylene chloride, and carbon tetrachloride, etc.

The chlorination agent preferably is chlorine. However, other compoundswhich will emit chlorine may be employed, such as SCI S Cl SO CI PCIetc.

The preferred bromination reagent is a mixture of Br and C1 Howeverother compounds which will emit bromine, such as, SBr S Br Br SO Br PBretc. can also be used. When employing a mixture of bromine and chlorineas the bromination reagent the molar ratios used are from about 0.5 toabout 2 moles bromine per mole of chlorine, preferably equimolar andeven more preferably an excess of chlorine, i.e. about 0.8 moles ofbromine per mole of chlorine.

The amount of halogenation reagent employed for step 2 is dependent onthe amount of halogen desired on the aromatic ring. The molar ratio ofhalogenation reagent ranges from about 1 to about 8 moles per mole ofadduct, preferably about 3.5 to about 5 and even more preferably about 4to about 4.5 per mole of adduct.

The compounds resulting from this process are halogenatedhalocyclopentadiene adducts of styrene, of the following structure:

' group consisting of fluorine, chlorine, bromine, alkyl of one to 10carbon atoms, preferably alkyl of one to six carbon atoms, and halogensubstituted alkyl of one to 10 carbon atoms, preferablyhalogensubstituted alkyl of one to six carbon atoms, wherein the halogen ischlorine, fluorine or bromine;

X is a halogen independently selected from the group consisting ofchlorine, bromine and mixtures thereof;

R and R are substituents independently selected from the groupconsisting of hydrogen and alkyl of one to six carbon atoms;

a is from 1 to about 5, preferably about 5 to about 5;

bisfromOto l anda+b=5 When a mixture of bromine and chlorine is used asthe bromination reagent to give tetrahalogenation, the resulting productwill contain a mixture of chlorine and bromine substituted on thebenzene ring. Generally about percent to about percent of the productwill contain three bromine atoms and one chlorine atom substituted onthe benzene ring with the rest of the product (about 80 to about 90percent) being the tetrabrominated product.

The most preferred embodiment is hexachlorocyclopentadiene and styreneas reactants. In order to simplify discussion, reference will be made tothe latter two compounds; however, it is recognized that otherhalogenated cyclopentadienes or styrene derivatives could be used intheir respective places.

Some of the halogenated cyclopentadienes that may be employed are asfollows: hexahalocyclopentadienes such as hexachlorocyclopentadiene,hexafluorocyclopentadiene, hexabromocyclopentadiene,pentachloromonobromocyclopentadiene, tetrachlorodibromocyclopentadiene,etc; monoalkyl pentahalocyclopentadienes, such asmethylpentachlorocyclopentadiene; methylpentabromocyclopentadiene;dialkyltetrahalocyclopentadienes, such asdimethyltetrachlorocyclopentadiene, dimethyltetrabromocyclopentadiene.

Some of the halogen substituted alkyl cyclopentadienes are:

Ci C1 (51 01 Cl 01 c1- c1 01 0mm 01 0112011201 Br UT TP Br- Br F F Y Brcnnnn F c.11 1"-3 lla Clix Some preferred novel compounds resulting fromthe process can be depicted as follows:

(R')b R I X (X). G Y

R R X X Y a b l. H H Cl Cl Cl 4 l 2. H NP Cl Cl Cl 5 0 3. H CH Cl Cl Cl4 1 4. CH, H Cl Cl Cl 4 I 5. H NP Cl 4 Br 8: 1 Cl* Cl 4 0 6. H H Cl BrCl 4 l 7. H NP Cl 3 Br & 2 Cl Cl 5 0 8. H NP Cl Br Cl 5 0 9. H H Br BrBr 4 l mixture of halogens (bromine and chlorine) on aromatic ring. NP

not present Having described the invention, below are working exampleswhich illustrate embodiments of the invention so that one of skill inthe art may practice the invention.

Unless otherwise illustrated, all temperatures are in degrees Centigradeand all amounts are in parts by weight.

EXAMPLE 1 Preparation of Diels-Alder adduct of styrene andhexachlorocyclopentadiene.

Into a 5 liter 3 neck flask was charged 4,095 g. ofhexachlorocyclopentadiene and this was heated to l50-l60 C. Styrene(1,578 g) was added over 5-6 hours. The temperature was maintained atl50-l60 C. A small sample removed from the reaction vessel one hourafter the addition was complete emitted no hexachlorocyclopentadieneodor. The flask was then heated at 150 C. under aspirator vacuum. After2 hours, the vessel was purged with nitrogen. The product collected was5,610 g. of a slightly yellowish solid with a melting point of 6773 C.Yield was calculated as 99 percent.

Analysis calculated for c H Cl zCl, 56.5

Found :Cl, 56.0 Infrared and NMR spectra confirm the assigned structure.

EXAMPLE 2 Chlorination of the Diels-Alder Adduct to a TetrachlorinatedProduct.

A three neck flash was charged with 377 grams of the adduct preparedfrom styrene and hexachlorocyclopentadiene, 377 milliliters ofhexachlorobutadiene and 10 grams of reduced iron powder. This mixturewas heated and held at -65 C. while gaseous chlorine was bubbled intothe reaction mixture with a rapid stirring. After 5 hours the evolutionof hydrogen chloride, as measured by weight pickup in a water trap onthe exit gas line, had slowed to a negligible rate. The mixture waspurged with nitrogen and filtered. The product was separated from thefiltrate on cooling to room temperature, and filtered off. The crudeproduct weighed 469 grams. The crude product was slightly yellow with amelting point of 127148 C. Extraction of this crude product with acetoneproduced an almost white product with a melting point of 140-150 C. Theyield was calculated to be about 91 percent. Elemental analysis andspectral data showed that the product was of the structure:

Equivalently good results are obtained when a catalyst of powdered iron(5.3 percent by weight) and powdered copper (1.32 percent by weight) isemployed.

EXAMPLE 3 Tetrabrominated Styrene-Hexachlorocyclopentadiene Adduct.

To a 250 ml. three-necked flask, equipped with a mechanical stirrer,addition funnel, immersion thermometer and reflux condenser, was charged75.4 g. (0.2 mole) of the adductof styrene and hexachlorocyclopentadieneand 5.3 g of powdered iron. To the stirred mixture, which was maintainedin the molten state (85-90) with an oil bath, was added 159.9 g (1.0mole) of bromine dropwise via the addition funnel during 4 hours. Afterstirring an additional 6.5 hours at 85 103 and then standing at roomtemperature overnight, the crude solid was thoroughly extracted withbenzene. The benzene extract was filtered and washed successively withsodium sulfite solution and then water. The solution was concentrated togive 120.1 g (86.4 percent yield) of crude product. The crude productwas purified via recrystallization from benzene after the benzenesolution had been treated with charcoal, m.p, 179180.5.

Analysis calculated for C l-l Br Cl C, 22.5; H, 0.6; Br, 46.2; C1, 30.7.

Found: C, 22.6; H, 0.6; Br, 45.8; C1, 30.6. EXAMPLE 4 Chlorination ofDiels-Alder Adduct to give the Tetrachlorinated Derivative.

A 2 liter, 3 neck flask was equipped with a nitrogen flow tube, astirrer, addition funnel, condenser, and thermometer. The flask wascharged with 188.5 g. of the adduct of styrene andhexachlorocyclopentadiene, 500 ml. of carbon tetrachloride and 5 g. ofAlCl This mixture was heated to 48 C and a solution of 5 g. of S Cl and490 g. of SO Cl added dropwise. The reaction mixture temperature rose to70 C. where it was maintained with external heating for the 5 hour addition period, and 2.5 hours after completion of the addition. Then anadditional 200 ml. of carbon tetrachloride was added followed by theslow addition of 200 ml. of water. The cooled reaction mixture wasextracted successively with 1,100 ml. H 0, 100 ml. 5% NaHCO and 1,000ml. of H 0. After drying and filtering, the volatile material wasstripped from the reaction mixture. The residue weighed 271.8 g. Thiswas recrystallized from carbon tetrachloride to give thetetrachlorinated styrene hexachlorocyclopentadiene adduct with a meltingpoint of 15 ll 54 C.

Calculated for C, H.,Cl Cl, 68.9

Found: Cl, 68.3...

EXAMPLE 5 Chlorination of the Diels-Alder Adduct to Give aTrichlorinated Derivative.

A flask was charged with a 7,514 g. (0.2 moles) of the adduct of styreneand hexachlorocyclopentadiene, 2.5 g of reduced iron powder and 150 ml.of acetylene tetrachloride. A total of 47 g. of chlorine gas was bubbledinto the reaction mixture which was maintained at approximately 55 C.The mixture wasthen cooled and filtered. The filtrate was washed withHCl, 10 percent sodium bicarbonate and water. The solvent was thenstripped off at reduced pressure to give an amber liquid as a residue.NMR analysis indicates the product to be a mixture of isomers of thetrichlorinated adduct of styrene and hexachlorocyclopentadiene.

Calculated for C, H Cl Cl, 66.4

Found: C1, 67.8 I

EXAMPLE6 'Chlorination of Diels-Alder Adduct to Give thePentachlorinated Derivative.

A flask was charged with 75.4 g. (0.2 moles) of the adduct of styreneand hexachlorocyclopentadiene and 250 ml. of carbon tetrachloride. Acatalytic amount of aluminum, mercury, iodine and aluminum chloride wasadded. Chlorine gas was then bubbled into the mixture, which was heldbetween 20 and 40 C., for 5 hours. After filtering the hot mixture an 84percent yield of crude product was isolated from the filtrate.Recrystallization from carbon tetrachloride gave the pentachlorinatedproduct with a melting point of 195195 0 I Calculated for c,,n,c|,,;c1,71.0

Found: Cl, 70.7. EXAMPLE 7 TetrabrominatedStyrene-Hexachlorocyclopentadiene Adduct.

To a 1,000 ml. three-necked flask, equipped with a mechanical stirrer,addition funnel, immersion thermometer and gas outlet tube, was charged301.6 g. (0.8 mole) of styrene-hexachlorocyclopentadiene adduct and 30g. iron powder. This mixture was heated to 84 C. and 800 g. of brominewas added dropwise during 1 1.5 hours while the reaction mixture wasmaintained at 90 C. after heating at 78 C for an additional 0.5 hours,the molten mixture was allowed to stand overnight. The residual brominevapors were largely flushed from the solidified reaction mixture with astream of N and then this solid was thoroughly extracted with benzene.After the benzene solution had beenfiltered, it was then washed withwater, sodiumsulfite solution and again with water and concentrated to850 ml. The desired product crystallized out and was washed with 400 ml.of acetone to give 400 g. (m.p. 178.5181.5 of tetrabrominatedstyrene-hexachlorocyclopentadiene adduct. A second crop was obtained andwashed with 70 ml. of acetone (81 g. mp. 171-177) The yield of desiredproduct based on the two crops was 86.8 percent.

EXAMPLE 8 Bromination of Diels-Alder Adduct to give the TetrabrominatedDerivative.

A solution of 192 g. (1.2 moles) of bromine and g. (1.2 moles) ofchlorine in 50 m1. of acetylene tetrachloride was added dropwise to astirred mixture of 3 g of antimony metal in a solution of 150.8 g. (0.4

mole) of the adduct of styrene and hexachlorocyclopentadiene and 125 ml.of acetylene tetrachloride at such a rate (during three-fourths hours)that the heat of reaction maintained the reaction temperature at 3955.The dark brown reaction mixture was stirred an additional 6 hours andthen the reaction was flushed with N free of the excess bromine andchlorine. Twenty milliliters of water was added and the light solid wasfiltered off. This was washed with water to give 215 g. (79 percentyield) of tetrabrominated styrene hexachlorocyclopentadiene adduct m.p.l72-l 75.

Calculated for C l-l Br Cl C, 22.5; H, 0.6; Br, 46.2; CI, 30.7.

Found: C,22.75;l-l,0.49-,Br, 43,78;Cl, 29.73. EXAMPLE 9 Bromination ofthe Diels-Alder Adduct to give the Tetrabrominated Derivative.

A 2 l. three-necked flask, equipped with a mechanical stirrer addition,funnel, dry ice condenser, immersion thermometer and gas inlet tube, wascharged with g. of iron, 439 g. (2.75 mole) of bromine, 99 g. (1.40mole) of chlorine (via the gas inlet tube), and 50 ml. of acetylenetetrachloride. During 4 hours, a solution of 150.8 g. (0.4 mole) of theadduct of styrene and hexachlorocyclopentadiene in 125 ml. of acetylenetetrachloride was added dropwise at such a rate that the reactiontemperature did not rise above 37. The excess halogenation reagent wasdistilled off by heating the reaction mixture and flushing it withnitrogen. An additional 250 ml. of acetylene tetrachloride was added andthe solution was treated with decolorizing carbon. After the solutionhad been filtered and concentrated 202 g. (72 percent yield) oftetrabromostyrene hexachlorocyclopentadiene adduct crystallized out,m.p. l75l79.

EXAMPLE l0 Bromination of the Diels-Alder Adduct to give theMonobrominated Derivative.

A solution of 46 g. (0.29 mole) of bromine and 22 g. (0.32 moles) ofchlorine in 50 ml. of acetylene tetrachloride was added to a stirredmixture of 10 g. of antimony chloride and a solution of 150.8 g. (0.4mole) of the adduct of styrene and hexachlorocyclopentadiene in 120 ml.of acetylene tetrachloride at such a rate (during minutes) that the heatof reaction maintained the reaction temperature at 42-44. The darkreaction mixture was stirred an additional 2 hours and then the reactionwas flushed with N free of the excess bromine and chlorine. Twentymilliliters of water was added to the clear solution and the decomposedcatalyst was then filtered off. The solution was concentrated andallowed to crystallize to give the monobromo styrenehexachlorocyclopentadiene adduct, m.p. l l6l26. Recrystallization fromhexane gave an analytical sample, m.p. l28l3 I.

The spectral and elemental analyses were consistent with the assignedstructure.

EXAMPLE 1 l Halogenation of the Monobrominated Derivative of theDiels-Alder Adduct to give the Pentahalogenated Derivatixe.

A solution of 768 g. (4.8 mole) of bromine and 340 g. (4.8 mole) ofchlorine was added during 3 hours to a stirred solution composed of 35g. of antimony chloride, 500 g. (1.1 mole) of the monobrominated adductof styrene and hexachlorocyclopentadiene and 700 ml. of acetylenetetrachloride. The addition was made at such a rate that the reactiontemperature did not rise above 50. After stirring an additional 3 hoursthe excess halogenation reagent was flushed off with a stream of N thesolid product was filtered off and washed with fresh acetylenetetrachloride to give 225 g. of crude product. This was recrystallizedfrom benzene to give a analytical sample of pentahalo styrenehexachlorocyclopentadiene adduct, m.p. l94-203.

Elemental and Spectral Analyses indicatedthat the product is a mixtureof pentahalogenated styrene-hexachlorocyclopentadiene adducts, averagingbetween three and four bromine atoms per molecule and seven and eightchlorine atoms per molecule.

An alternative method of preparing the halogenated halocyclopentadieneadducts of styrene would be as follows:

1. react a compound of the structure with a halogenating agent so thatthe aromatic ring is halogenated; this may be performed in the presenceof metal catalysts, such as, iron; R hydrogen or alkyl of one to sixcarbon atoms; X is bromine or chlorine: See Textbook of OrganicChemistry, Noller, Second Edition (1958) W.B. Saunders & Co., page 326and following.

2. dehydrohalogenate the side chain with alcoholic KOH, see OrganicChemistry, Cram & Hammond Second Edition McGraw-Hill Book Company(1964), page 330 and following and US. Pat. No. 2,569,l3l; and

3. reacting the halogenated styrene with a halocyclopentadiene (such ashexachlorocyclopentadiene) in a Diels-Alder reaction. See US Pat. No.2,606,9l0 and Ser. No. 51,012, filed on even date herewith.

The halogenated styrene cyclopentadiene adducts are useful as fireretardant additives for various polymers and plastics compositions suchas ABS, high impact polystyrene and others. Some of the plasticcompositions in which these adducts could be used are described in US.Pat. No. 3,403,036. Preferred compositions are ABS and others describedin Ser. No. 51,008 filed on even date herewith.

We claim:

1. A compound of the formula wherein R and R are independently selectedfrom the group consisting of hydrogen and alkyl of one to six carbonatoms, X is a halogen selected from the group consisting of fluorine,chlorine and bromine; Y is independently selected from the groupconsisting of chlorine, bromine, fluorine, alkyl of one to 10 carbonatoms and halogenated alkyl of 'one to 10 carbon atoms, wherein saidhalogen is selected from the group consisting ofchlorine, bromine andfluorine; X' is independently selected from the group consisting ofchlorine, bromine and mixtures thereof; a is from about 4to5,bis0to landa+b=5.

2. The compound of claim 1 wherein X is chlorine.

3. The compound of claim 1 wherein Y is chlorine.

4. The compound of claim 1 wherein X and Y are chlorine.

5. The compound of claim 1 wherein R is hydrogen.

6. The compound of claim 1 wherein R is hydrogen.

7. The compound of claim 1 wherein X is a mixture of chlorine andbromine.

8. The compound of claim 1 wherein X is chlorine.

9. The compound of claim 1 wherein X is bromine.

10. The compound of claim 7 wherein X and Y are chlorine.

11. The compound of claim 9 wherein X and Y are chlorine.

12. The compound of claim 10 wherein X and Y are chlorine.

13. The compound of claim 1 of the structure 14. The compound ofclaim lof the structure

2. The compound of claim 1 wherein X is chlorine.
 3. The compound ofclaim 1 wherein Y is chlorine.
 4. The compound of claim 1 wherein X andY are chlorine.
 5. The compound of claim 1 wherein R is hydrogen.
 6. Thecompound of claim 1 wherein R'' is hydrogen.
 7. The compound of claim 1wherein X'' is a mixture of chlorine and bromine.
 8. The compound ofclaim 1 wherein X'' is chlorine.
 9. The compound of claim 1 wherein X''is bromine.
 10. The compound of claim 7 wherein X and Y are chlorine.11. The compound of claim 9 wherein X and Y are chlorine.
 12. Thecompound of claim 10 wherein X and Y are chlorine.
 13. The compound ofclaim 1 of the structure
 14. The compound of claim 1 of the structure15. The compound of claim 7 wherein from about 10 to about 20 percent byweight of said compound contains three bromine atoms and one chlorineatom substituted on the benzene ring and from about 90 to about 80percent by weight of said compound contains four bromine atoms.